When transporting or stacking bulk containers a locking device is needed to secure the containers to a base. The base could be an integral part of a transport vehicle, such as: truck chassis, railcar, aircraft, or ship hatch. Additionally, a base could be an adjacent container, when the containers are stacked onboard ships, rail cars, or in container yards. These locking devices are numerous including: cones, twist locks, lashing bars and other systems. Although these devices and systems are currently used to connect containers to various bases, they posses a number of disadvantages that make them unsafe and inefficient.
Currently a device called a cone is used when connecting containers to a ship's hatch or other containers. Cones come in three forms, manual cones, automatic cones and below deck cones. Cones are generally two tetrahedron shaped objects wherein the bases of the tetrahedrons are rectangular in shape and the bases of the tetrahedrons are base to base, such that the cones, when in an unlocked position, are in the shape of an octahedral diamond. At least one of the tetrahedrons can rotate such that the bases are no longer aligned, and when inserted between container corner castings can connect containers.
Manual cones are inserted into corner castings of a container that will connect to a ship hatch or another container. These cones are inserted into the corner castings manually when a lifting device raises the container off a chassis. The cone is inserted into the corner casting access slot of a container; and the head that is in the access slot is manually turned such that the head is locked into the corner casting. Once the cones are inserted in all four lower corner castings the container is lifted to its position on the ship and lowered onto the deck or another container where the bottom head of the cone mates with the deck or upper corner fittings of a lower container. The bottom head is then manually turned such that the head is locked into the corner casting thereby locking the container to a base.
Manual cones have a number of disadvantages. Cones require manual locking and unlocking, incurring additional labor costs and placing humans in potentially dangerous situations. Additionally, they require personnel to work both on vessels and on the ground, again increasing labor costs. Laborers are required to work around and beneath suspended containers, which weigh many tons even when empty. In addition, when cones are not inserted or turned into the locking position they can become detached from a container causing additional problems, such as an unsecured connection between a container and a base or, when being hoisted by a lifting device, the cone can fall from the container, injuring or killing personnel. Further, a cone is one form of a number of similar locking devices used to secure containers, such that additional equipment and additional purchase and maintenance costs are incurred. Lastly, recent U.S. regulations have required that all cones used at U.S. ports be of the automatic type due to safety considerations, causing the manual cones to be unsuitable for use in the U.S.
Automatic cones are similar to manual cones in design however, when the automatic cones are mated to a base they lock automatically. Although automatic cones eliminate the need to manually lock containers to a base, they still require a manual release, still placing personnel into dangerous work environments. For instance, containers are often stacked five, six or even seven high on board ship hatches, requiring personnel to work at great heights. Furthermore, automatic cones have a number of the disadvantages that manual cones posses, including: requiring personnel to work both on vessels and on the ground, the cones can fall free injuring or killing personnel below, and an automatic cone is one form of a number of similar locking devices used to secure containers such that additional equipment and therefore additional purchase and maintenance costs are incurred.
The twist lock is yet another device that is used to connect containers to a chassis. Twist locks are comprised of a locking pin and a handle. The locking pin has a shaft that runs through the bolster of a chassis, which can rotate. The locking pin also has a head which is rectangular in shape at its base and is cone shaped at its top. Bulk containers have corner castings with access slots at their top and bottom such that when the container is mounted on a chassis the head of the twist lock can mate with the access slot. The access slot is an opening in the corner casting of a container with which the pin head can mate when the pin head is in an open position but cannot mate or disconnect when the pin is in a locked position. When the locking pin mates with the corner casting, a handle connected to the shaft of the locking pin is manually turned, which in turn, twists the pin head inside of the corner casting such that the base portion of the pin head connected to the shaft is now askew in relation to the opening in the corner casting access slot, such that the container cannot be disconnected from its base.
Although twist locks address some of the limitations of the previous devices, they also posses a number of disadvantages. Still, the system requires a person to manually open and close the twist locks in order to connect or disconnect a container from its transport base. The manual requirement can put a person in a dangerous work environment where heavy machinery is lifting tons of equipment thereby putting an individual at risk of injury or death.
A second disadvantage of twist locks is the procedures that are adopted to prevent personnel from having to unlock containers from their bases in dangerous environments. A common practice is to require personnel to unlock containers from a chassis as the container enters a yard to prevent them from having to do so around heavy machinery or suspended containers. This method can create a number of dangerous situations in a yard. First, the container is no longer connected to the chassis, it is merely resting on the chassis. If an accident were to occur, the container is not connected to chassis, causing an unpredictable and potentially dangerous situation. Additionally, while driving around a yard, the twist locks often turn accidentally into the locked position requiring the driver to exit the safety of his vehicle to reopen the twist lock, thereby defeating the goal of the procedure. It is not uncommon for lifting devices, such as top picks and cranes, to drag or lift the truck along with the container. These are dangerous situations for drivers and anyone else that might be in the area. A third disadvantage is that a twist lock is again one form of a number of similar locking devices used to secure containers such that additional equipment and therefore additional purchase and maintenance costs are incurred.
Another disadvantage of current methods of securing containers to transport modes relates to the rail industry. When containers are stacked one or two high on rail cars, the lower container simply sits in the well of the rail car and has no means of being connected to the car. This is because there is no way to access the lower corner fittings of a container that is sitting in the well of the rail car. As a result, there is no way to manually unlock a manual or automatic cone or twist lock.
An additional disadvantage of these devises is the number of different locking devices utilized to perform a single function, connecting or disconnecting container from a base. A single, fully automatic, device should be used to connect containers to chassis, railcars, ship hatches or other containers to improve safety and efficiency between different transport modes.
Another disadvantage of these devices is that they adversely effect crane cycle times by 15 to 20% during vessel loading and discharging operations.
Inventions have been developed to overcome the above mentioned problems including Del Aqua's in 1982 (U.S. Pat. No. 4,341,495) and Cain's in 1976 (U.S. Pat. No. 3,980,185) These prior art forms however were not commercially viable; because the components of the inventions are intrusive into the interior space of a container, susceptible to being damaged by equipment or cargo moving into and out of containers, and would require modifications to the doors of a container. Also, these inventions require all four upper corner castings of a container to be engaged by rotatable twist locks of a spreader which is not possible when using machines which only engage two of the upper corner castings or sites that use fork lifts to lift containers. Lastly, the number of moving parts that comprise these are forms would be difficult and expensive to maintain in a fleet of containers spread around the world. In another invention by Walker in 1992 (U.S. Pat. No. 7,014,234), the disadvantages of Del Aqua's and Cain's are overcome, however this prior art from has a disadvantage caused by the non-standardized depth of twist locks used to connect containers together on ships.
It is common practice in container yards to simply stack containers in piles without securing them to one another, because it is not required by federal or state safety regulations. Additionally, equipment costs are prohibitive; cones are provided by vessels, not stevedoring companies or container yards. The additional labor required to set, lock and unlock connecting devices is also costly.
There are hazards inherent by not connecting the containers together while in a stacked configuration, such as building a disorderly pile. While one container is being added to a stack of containers, the container being stacked may nudge another container in the stack, causing it to fall. The fallen container may not be obvious to the operator of the lifting device. For obvious reasons, this is an extremely undesirable and dangerous situation, potentially causing great damage and injury.
As can be seen by existing solution attempts, the problem of providing a safe, economical, universal, and automatic means to secure containers has not been fully addressed. Existing methods can require placing humans in dangerous situations, require many costly parts, require manual locking and unlocking, and create disorderly piles.
What is needed is a locking device that can safely, securely, and automatically lock and unlock a container from a base quickly, requiring a minimum of direct human manipulation. What is also needed is a locking device that has no detached parts, eliminating that safety concern. What is additionally needed is a locking device that meets current safety standards and regulations. What is further needed, is a locking device that can be engaged on rail cars. What is again further needed is a locking device that does not excessively protrude into the interior cargo space of a container. What is still further needed is a locking device that can be automatically disengaged by the insertion of fork lift tines. What is again needed is a locking device that can enable the lifting of a container by just two of the four upper corner castings. What is also needed is a locking device that can be applied to existing modified containers, without the need to modify supporting equipment. What is finally needed is a locking device that provides a means to stack container in orderly and stable piles.